One of Airbus first models of the A350 XWB is seen at an event to show off the jet's interior in Hamburg, Germany, on April 7, 2014. / Ben Mutzabaugh, USA TODAY

by Ben Mutzabaugh, USA TODAY

by Ben Mutzabaugh, USA TODAY

HAMBURG - Airbus showed off the interior of its new Airbus A350 XWB for the first time ever Monday at a press event at its Hamburg facility. Airbus' mock-up of its "MSN002" flight-test version of the A350 featured a an economy cabin laid out in a nine-abreast (3x3x3) configuration. The business-class cabin featured lie-flat seats in a four-abreast (1x2x1) layout.

While the unveiling of the interior is a significant development for the A350, the version showed on Monday is just a mock-up by Airbus that shows potential options its airline customers can choose for their versions of the jet. It will be up to individual airlines to decide both the density and types of seats they'll choose for their A350s. Qatar Airways is scheduled to be the first airline to fly paying passengers in the A350. That carrier is scheduled to take delivery of its first A350 by the end of 2014.

Airbus' A350 will seat 250 to 300 in typical configurations, Chris Emerson, senior vice president of marketing at Airbus, said Monday at the unveiling of the A350 interior. But the aircraft could seat as many as 400 in an all-coach, "high-density" configuration that's common among discount carriers.

Made largely from carbon composite materials like Boeing's Dreamliner, the A350 made its first flight in June 2013 and is in the process of flight testing so that it can be certified for airlines to fly. The A350 remains on schedule to be delivered to launch customer Qatar Airways by the year's end, Emerson said.

As for the passenger experience on the A350, Emerson touted the new jet's wider-than-normal 221-inch cross section. He said the extra width on the wide-body jet would give customers a more-comfortable seat width of 18 inches â?? provided airlines that buy the jet don't install more than nine seats per row.

While that nine-abreast count is the layout Airbus envisions for the economy class, airlines are free to configure the jet as they see fit. And that could include a "high-density" layout that would pack in 10 passengers per row in coach class.

When asked for his thoughts on the possibility that Airbus' A350 customers could opt for such a layout, Emerson responded "airlines know best" what works for the markets they serve.

"Our obligation (is) to give them that palette, the options that help them meet best their marketplace," he added. "Every marketplace is different. You have got an a cabin that can be as efficient as you want. We leave that to them."

Emerson also cited a subtle change to the cabin walls in the A350's design, saying they're more vertical than on other comparable aircraft models.

"You will feel there's no encroachment of the side wall. It doesn't curve into you," he said.

Among the other A350 cabin features cited by Emerson: ever-larger overhead storage bins. The A350's bins are designed to hold five roll-aboard bags side-by-side in a standard bin.

Passengers "want to carry more on to the aircraft," Emerson said. "The worst is (when) you're the last on to the plane and there's no room for your carry-on luggage."